Hydraulically actuated crimping tool



Aug. 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULICALLY ACTUATED CRIMPING TOOL 7 Sheets-Sheet l Filed July 10,1957 Aug. 4, 1959 H. R. FISCHER' ETAL 2,897,703

HYDRAULICALLY ACTUATED CRIMPING Toor.

Filed July l0, 1957 7 Sheets-Sheet 2 BY m ATTDRN Aug. 4, 1959 H. R.FISCHER ET AL 2,897,703

HYDRAULICALLY .ACTUATED CRIMPING TOOL '7 Sheets-Sheet I5 Filed July 10,1957 Aug 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULIC/'ALLY ACTUATED CRIMPING TOOL Filed July 10, 1957 7Sheets-Sheet 4 ATTRNEY Aug. 4, 1959 H. R. FISCHER ET AL 2,897,703

HYDRAULICALLY ACTUATED CRIMPING TOOL Filed July 10. 1957 7 Sheets-Sheet5 Aug. 4, 1959 H. R. FISCHER ETAL 2,897,703

HYDRAULICALLY AcTuATED CRIMPING TooL.

'7l Sheets-Sheet 6 Filed July 10, 1957 f a l f l g QQ N Aug. 4, 1959 H.R. FlscHER ETAL 2,897,703

HYDRALICALLY ACTUATED CRIMPING TOOL Filed 'July 10, 1957 7 sheets-sheet7 Tlc'l.

BY WM/5M ATTORN EY 2,897,703 Patented Aug. 4, 1959 HYDRAULECALLYACTUATED CRMPING TOL Howard R. Fischer and Marcel P. DHaem, Utica, NSY.,assignors to Chicago Pneumatic Tool Company, New York, NX., acorporation of New Jersey Application .lilly l0, 1957, Serial No.670,976

i8 Claims. (Cl. 81-15) This invention pertains to a pneumaticallypowered compressing tool that is compact in size and is adapted to beheld in the palm of the hand when operated. The tool is particularlysuited for use in wire terminal crimping operations, and the like.

A general object of the invention is to provide an improved andpractical pneumatically operable compressing tool of small size that isheld in the hand when operated.

A feature of the invention is a highly efficient mechani cal movement ofelements powered by a piston driven wedge, whereby la movable jaw iscaused to be compressively closed upon a stationary jaw.

A further feature of the invention is a practical trigger controlledarrangement of valves for effecting pneumatically upon each actuation ofthe trigger a single reciprocating movement of the piston driven wedge.

Another feature of the invention is a-manually operable push buttoncontrol arrangement for opening by pneumatically powered means the jawsof the tool to enable insertion of work material between them.

Another feature of the invention is a manually operable latch for safelyholding the jaws locked in open position after the push button has beenreleased.

A still further feature of the invention is an interlock safetyarrangement, whereby a compressive action of the tool cannot be effectedwhile the jaws are held in open position.

Another object of the invention is to provide a practical hand toolwherein all of the foregoing yfeatures are embodied.

The invention further lies in the particular construction of its variousparts, and also in their general arrangement and cooperative associationwith one another to effect the results intended herein.

The foregoing and other objects, features and advantages of theinvention will appear more fully hereinafter from a consideration of thedetailed description which follows, taken together with the accompanyingdrawings wherein an embodiment of the invention is illustrated. It is tobe expressly understood, however, that the drawings are for purposes ofillustration and description, and they are not to be :construed as`delining the limits of the invention.

ln the drawings:

Fig. 1 is a longitudinal section through the tool;

Fig. 2 is a plan section on the line 2-2 of Fig. l;

Fig. 3 is a cross section on the line 3-3 of Fig. 2;

Fig. 4 is a cross section on the line 4-4 of Fig. 2;

Fig. 5 is an enlarged sectional view showing the latch block in alatched condition, holding the jaws of the tool in fully open position;

Fig. 6 is a cross section on the line 6-6 of Fig. 5;

Figs. 7 and 7a are enlarged sectional views which schematically show thecondition of the tool preparatory to effecting operation of the tool anda consequent crimping action upon terminal wire elements receivedbetween the dies, Fig. 7a showing the valve system in normal position;

open position.

Figs. 8 and 8a are enlarged sectional views which schematically show thecondition of the tool upon completion of the forward stroke of the toolin effecting a crimping action;

Fig. 9 is a sectional view which schematically shows the relation of thecontrol and pop-off valves at the end of the return stroke of the wedgeand while the `trigger is still held depressed; and

Fig. l0 is an enlarged sectional View which shows the valve systemimmediately after the trigger has been actuated.

The tool illustrated in the accompanying drawings includes a housing 20providing a drive or work piston chamber 21 which is closed at its rearby a valve block or head 22. The opposite end of the piston chamberopens through a reduced area 23 into a forward chamber 24. The latteropens out through the bottom and front end of the housing. Disposedwithin chamber 24 in parallel spaced relation to each other is a pair ofside bearing plates 25, 25'. These plates, as appears in Figs. 2 and 3,project in part through the front end and through the bottom of thehousing. An upstanding arm 26 of a yoke member 27 is rigidly retainedbetween the forwardly projecting portions o-f the side plates by meansof pins 28. The inner walls of the side plates serve as bearing facesfor a tail end or block portion 29 of a ram 31. The latter has a reducedcylindrical shaft 32 which continues forwardly from the ram block 29 andslides through a complementary opening in the yoke arm 26. A ram jaw 33has a tail piece 34 retained in an end bore of ram shaft 32 by asuitable pin. Jaw 33 represents the movable member of a pair of opposedjaws. The other jaw 35 is stationary, and is an integral part of theyoke member. Jaws 33 and 35 are adapted to accommodate separate halvesof a pair of wire terminal crimping dies 36, 37 (Fig. l). The particulardies shown are for purposes of illustration only. The dies serve, whenclosed under pressure, to effect a crimping action on wire terminalelements 38 disposed between them (Figs. 7 and 8).

The movable jaw 33 is normally held in its forward or closed position(Fig. l) by a spring loaded holding piston 39. The latter ispneumatically operable to move against this spring load so as to drawthe ram jaw to This piston moves in a cylinder 41 formed by the housingin the upper area of chamber 24. An open rear end of this cylinder isclosed over by a washer plate 42. which abuts against a suitable snapring retained in an internal groove of the cylinder. The piston carriesa rod y43 which is slidable through the washer plate into the upper reararea of chamber 24. The free end of an upstanding piece 44 of a draw bar45 is retained at 46 upon an externally projecting end of the pistonrod. The draw bar slides in a channel track 47 formed in the undersideof the piston cylinder. Integral with the forward end of the draw bar isa fork having a pair of depending ngers 48. The latter depend freelyinto a pair of vertical slots 49 formed on opposed inner faces of thearms 51 of a bifurcation `formed in the rear of the nam block 29. Coilspring means 52 disposed about the piston rod 43 and loaded between thepiston and the washer plate constantly unges the piston to a normalforward position (Fig. l), wherein the lingers 48 of the draw bar holdthe movable jaw in its forward or closed position.

Pneumatic control means (Figs. 1, 2, 4, 5, 7, 7a) is provided to actuatethe holding piston 39 to cause the movable jaw 33 to be drawn to itsopen position. To this end, the valve block 22 has a supply inlet 53which is adapted for connection by a hose line, not shown, to a sourceof pressure air. A branch passage 54 from this inlet leads through thevalve block and housing to a chamber 55 of a check valve 56. The latteris continuously under the load of pressure air in passage 54,andrnormally seals chamber 554 offA from a passage 57. The latter.passagej communicates. by radial port 58 throughthechamber 59 ofA aninterlockslide member 6l with afurther passage 62 leading to the chamberof.

cylinder 41ahead of the holding-piston. The check valve has astem63which extends freely through pas.- sage57 into an enlarged counterhore64.that opens to the'outside of the housing. Threaded on the end ofthis, stem is a push button 65 that projects inpart from thehousing, andhas a loose tincounterbore 64.y The check valve is unseated by manuallydepressing the push..

bullion.A While the checkvalveisunseated, pressure air owsfthrough theassociated passages to the holding piston 39,. after. slidingtheinterlockvalve y61 .tothe left against the load of a light spring V,66,whereupon 'the'hold-U ing'pistonis forced tothe right against theloadofits springs 52, and the drawbar 45 `is caused to draw-by means of itsfingers 48..the movable jaw 3310 its fully open position, as appears in.Fig. 5.- WhileY the push button is manually helddepressed, an O-ring 67on the inner end of the latter seats upon a shoulder 68 and preventsescape of pressure air around the outer diameter of the push button.

After push button 65 is manually released andthe check valve thusreseated, jaw 33 is returned toits normally closed position by theholding pistonl as the latter restores under the load of spring means52. As piston 39 restores, air in the piston chamber ahead of theVpiston vents.to atmosphere around the outer diameter of the pushbutton.

The primary function of the pneumatically operable holding piston is topermit jaws 33 and 35 to be drawn apart so as to enable insertion ofuncrimped wire terminal elements 38 between the dies 36, 37. After thelatter-action is effected and the push button is released, theholdingpiston under the load of its springs carries the die 36 of the movablejaw into abutment with the terminal wire elements 38 and thereby holdsthe-latter in place (as in Fig. 7). Pneumatically poweredmeans isprovided to next pressurize the jaws and dies so as to etect a crimpingaction upon the wire terminal elements.

This pneumatically powered pressurizing means includes a lever bar 69having a slightly rounded nose 71 at its forward end. This nose extendsinto the bifurcation formed inthe rear of the ram block 29 and it abutsagainst. the back wall 72 of the bifurcation. The nose endof the leveris loaded into abutment Withwall 72 of the ram block serve to anchor thesprings at the opposite end. A cross shaft 76 projects through oppositesides of.the.rear portion of the lever. Each projecting end of -thisshaft is iitted with bearings carrying a roller 77. An-eccentric camface 78, forming the rear end of the lever, is normally in closeproximity to the peripheral surfaceof a large roller 79 which hasastationary position relative to the housing.

Roller 79v is carried by bearings fitted on a stationary cross shaft 81.The vends of this shaft are supported in complementary holes formed inopposed bossed portions Y 82 Lof thesideplates 25, 25. The side platesand cross shaft 81 are retained in the housing by headed bushings 83ttedin opposite sides of the housing and by bolts 84 threaded throughthe vbushings into opposite ends of the cross shaft'.

When the movablev jaw 33 isdrawn to open position (Fig. 5) by theholding piston as previously described, the eccentric eam-end 78' of thelever is caused to ride down-overthe large roller as the oppostite'noseend 7l of the lever pivots against the back wall 72 of the bifurcationof the ram block. The underside of the lever is limited in its downwardmovement by a stub roll pin supported in the side plate 25. An underlipS5 formed at the forward end of the lever, and an upper lip extension 86of a spring plate mounted on the latter, respectively extend under andover the ram block 29, whereby the lever is guided in a vertical planeduring its pivoted movement.

lf it is desired that jaws 33, 35 remain open for any length of time,locking means is provided to' lock them in this open position, so as toavoid the necessity of continuously holding the push button 65depressed. This locking means comprises (Figs. l, 5, 6) a latch block 87which is arranged below ram block 29. This latch block is verticallyslidable between the side plates 25, 25. It is guided in this slidingmovement by the rear end wall SS-of the yoke arm 26 and by a-pair ofstub roll pins 89 carried by the sideplate 25.'v When'the ram member isdrawn to its fully open position, the tail blockr 29 thereof is drawnclear of the latch block 87'and the cylindrical shaft 32 of the rammember is moved to a position above the latch block. A semi-circulartrough 91 in the latter is adapted to engage about the `ram shaft infront of a shoulder 92 of the ram block, when the latch block is movedupwards. Shoulder 92 abuts against the latch block in this movedposition ofthe latter, whereby the ram member is held inits moved orfully open position.

A manually operated cam lever 93 is arranged to effect up or downmovement of the latch yblock and consequent engagement or disengagementof the latter with the ram member. This lever is substantiallytriangular and is pivoted at its vertex on a cross pin 94 supported inthe housing. A nosed corner ofthis lever extends into anunder-bifurcation 95 of the latch block and is pivotedl therein on a pin96 supported by the arms of the bifur cation. A linger 97 projectingfrom the lever to the outside of the housing enables manipulation of thelever,

whereby the latch block may be vertically'raisedor lowered relative tothe ram-shaft. The latch block retains its moved position by frictionmeans provided by a pair of ball elements 98. These are spring -loadedoutwardly of the latch block so as to frictionally engage opposed facesof the side plates25, 25.

After-the latch block is disengaged fronrthe ram shaft, the movable ramjaw 33 will be automatically returned by'the springrloaded holdingpiston39to normal position. As the ram jaw Vrestores,lthe `lever barV 69will be caused to pivot in a vertical plane to its normal hori Zontalposition, as in Fig. l, being aided iu this respect by the side springsr'73. ln the cvent of an abnormal overrise of lever 69 aboveitshorizontal position, the upper rear area thereof will strike theundersideiof the closely overhanging draw bar 45. l'n thisaction thespring lip 86 will be forced down upon thetail block and will yieldslightly, whereby damage to theflever, that might .otherwise occur ifthis upper lip were rigid,l is avoided.

If wire terminal elements :5S-have been previously disposed between thedies for a crimping action, the mov.

This wedge has a normal positioirlas in Fig. l, between the pistonchamber 2i and the forward chamber 24. An axially extending tail shanklill of the-wedge is retained by a suitable pin in a forked member 102..The forked member has an axial extensionV which is retained by athreaded portion and nut means 10S-to a driveV or work piston v1041.-.

The latter reciprocates in piston` chamber n 21. Lengthwivse of theunderside of the wedge is a chan bearings.

nel track 165 in which is slidably received an upper portion of anelongated thick center rail 106 of a ladder roller cage 167. This centerrail or bar carries transversely thereof a succession of pin typerollers 169 which, with the exception of at least the rst one S, areneedle The ends of the several rollers project from opposite sides ofthe center bar about midway of the upper and lower surfaces of thelatter, whereby an upper rail portion and a lower rail portion areprovided (Figs. 3, 4). The lower portion is adapted to ride in anunderchannel track r11 formed lengthwise of a tlat surface of an upperportion of a trigger supporting piece 112 of the tool.

The latter piece or section is assembled between the lower portions ofthe side plates 25, 25. To this end, the side plates provide a pair' ofopposed shoulders 113 (Figs. 3, 4) lengthwise of their inner faces. Anarrow underportion 114 of section 112` depends between these shouldersand projects between the bottoms of plates 25, 25 to the outside of thehousing. The upper portion of the trigger supporting section provideslongitudinal shoulders 115 iwhich overlie the shoulders 113 of the sideplates. The projecting ends of the rollers of the roller cage areadapted to roll upon the shoulders 115 as` the center rail 136 of thecage moves in the trackway 111. Depending legs 116 of the wedge freelystraddle the center rail 1416 and are adapted to ride over the rollersof the roller cage as the wedge moves.

As the wedge is driven forwardly by the work piston 104., it rapidly andsmoothly rides over the needle bearings of the roller cage to engage andto pivot the ram lever 69 upward. In this movement of the wedge relativeto lever 69, the side rollers 77, which hang in part below theunder-edge of the lever are engaged by a cam varying upper surface 117of the moving wedge. A slot 118 in the nose of the wedge is provided toavoid intert ference ywith a projecting lower corner 119 of the lever,

so that the latter corner will not strike the wedge. As the rising camsurface of the rapidly moving wedge moves against and under the rollers77, it pivots the ram lever 69 upwards and forces the eccentric earn endof the lever over the surface of the large roller 79. In this action,lever 69 straightens out to its horizontal position, whereby a strongcompressive force is transmitted through the ram jaws and dies to effecta crimping action upon the Wire terminal elements 38, as appears in Fig.8.

rl`he rst member 1113 of the roller elements of the roller cage isintended to provide a slight frictional drag on the cage so as to enablea rapid movement of the wedge over the needle bearings and a consequentrolling rather than a skidding movement of the cage over the shoulders115. Due to the friction roller 1618, the cage moves relatively slowerthan the wedge, so that the Wedge is fully supported along its undersidewhen it applies a final strong lifting force to lever 69. The frictionroller 108 comprises (Fig. 4) a pair of pin elements slidably disposedin opposite ends of a cross bore of the center rail 106, and anintermediate spring which presses the pins outwardly so as tofrictionally engage the ends of the pins with the side plates 25, 25. Anupstanding lug 121 formed at the rear of the center rail of the rollercage extends into a vertically deeper end portion of the under track 105of the wedge. rl`he resultant shoulder 122 formed in the underside ofthe wedge is adapted to engage this lug on a return movement of thewedge and thus carry the roller cage back to normal position. ln thelatter action, an opstanding lug 123 (Fig. 8) at the rear of a sideshoulder ,t 1. will prevent the roller cage from overriding its normalposition.

The work piston 104 that drives the wedge is pneumatically powered, andis reciprocated in response to pneumatic uid caused to How by a triggercontrolled arrangement of valves (Figs. l, 2, 7, 7a, 8a, 9, 10).

Operating pressure air is supplied to the valve block 22 by a hose line,not shown, connected to the inlet 53 (Figs. 2, 7a). A pressure airdistributor valve 124 is slidable in a chamber formed by a bushing 125fitted in an open ended bore of the valve block. The opposed ends of thebore are sealed over in suitable manner by the elements 126 and 127.Valve 124 has a reduced central portion 123 which extends freely througha central neck passage 129 of the valve chamber. A conical shoulder 131at one end of the reduced valve portion normally seats over an opposedO-ring so as to seal an annular supply inlet channel 132 from the neckpassage 129 and from radial ports 133 that lead out of the neck passageto a passage 134 communicating with the work piston chamber 21. When theconical shoulder 131 is seated, an O-ring 135 mounted in a shoulder atthe opposite end of the reduced portion 128 of the valve is unseatedfrom the opposite end of the neck passage 129, whereby the latterpassage is vented by a port 136 to atmosphere. When valve 124 is in itsopposite position, as in Fig. 10, the O-ring 135 is seated so as toclose the neck passage 129 olf from the vent, and the conical shoulder131 is unseated so as to communicate passage 129 with the supply inlet53.

After turning a supply valve on, not shown, in the hose line connectedto the inlet 53, the tool is conditioned, as in Figs. 7 and 7a, foroperation. Pressure air thereupon ilows through the inlet 53 into thebranch passage 54 leading directly to the chamber 55 of the check valve56, the function of which was earlier described. Branch passage 54 alsoconnects directly by a lateral line 137 to the forward ends of thechambers 138 of a pair of return pistons 139 (Figs. 2 and 7). The latterhave elongated stems 141 which pass through the main piston chamber andare anchored at their ends 142 in diametrically opposed portions of thework piston. The chambers 138 of the return pistons are formed forwardlyof the work piston chamber in the wall of the housing of the tool. Thetotal of the effective areas of the return pistons is relatively lessthan that of the work piston.

Pressure air admitted to the inlet 53 also ows (Fig. 7a) into theannular channel 132. From the latter it enters a radial port 143 to acentral passage 144 in the valve, and then passes out at the lower endof the latter through a radial port to the lower end 146 of the valvechamber, just above the inner area of an enlarged endhead 147 of thevalve; whereby the conical shoulder 131 of the valve is held seated overthe neck passage 129, and the 0ring 135 is held unseated from theopposite end of this passage so that the latter is open to vent 136. Theradial port 133 leading from passage 129 into the work piston chamber 21is also vented in this normal condition of the distributor valve.

A branch passage 148 leading oi the annular channel 132 connects with achamber 149 of a throttle valve 151. The latter is normally seated overan O-ring so as to seal chamber 149 ott from a passage 152. A reducedstern portion of the throttle valve extends freely through the latterpassage to the outside of the valve block. A retainer 154 xed on theright end of this valve stem carries an O-ring which is normallyunseated from the adjacent open end of passage 152, whereby the latteris normally vented to atmosphere. Fitted to the tail end of the throttlevalve is an arm 156 of a slide member 157 which is slidable in acounterbore 158 of the valve block. This counterbore is a continuationof a Slightly narrower elongated bore 159. The latter extends throughthe bottom wall area of the housing and opens (Fig. 7) out into a radialrecess 161 at the underside of the housing. An elongated draw rod 162eX- tends slidably through both bores 153, 159 and through the slidemember 157. A threaded end portion of the draw rod projects in part tothe outside of the slide body and carries an adjustable retaining nut163 threaded into abutment with the slide member. A coil spring 164compressed in the counterbore between a shoulder of 'the Vlatter andanfopposed endof the slide member constantly urges the draw rod 162rearwardly, whereby the throttle valve 151 is normally held seated. Thepres'- sure of this coil spring 'upon the throttle valve is adjustableby tightening or loosening the retaining nut 163.

A hooked free end 165 of the draw rod extends into the recess 161 of thehousing and is attached to a hooked' 'trigger 171.V The latter pivots at1724 in the bifurcation 168.

It is clear that a counterclockwise.movement of the trigger 171 (Fig. 8)will act to press the throttle valve forwardly, as in Fig. l0, wherebythe Olringfon retainer 154 will be seated to close passage 152011 fromvent, and the throttle valve 151 will be unseated to communicate the airsupply chamber 149 to passage 152. Following this action, pressure airsupplied over passage 148 to chamber 149 will enter passage 152 vfromwhere it will flow over a branch 173 in the valve block to thedistributor valve chamber immediately below-the underside 174 of anenlarged head end 175 of the distributor valve. The area of theunderside 174 of thishead end is relatively greater than the inner area146 of the opposite head end 147, so that the greater pneumatic pressureacting on the area 174 shifts the distribution valve from its normalposition to its opposite position as in Fig.l 10. This shift unseats theconical shoulder 131 and seats the O-ring 135, whereby the neck passage129 is open to the pneumatic supply line 53 at one end and is closed atits opposite end from vent 136.

Pressure air now enters through passages 129, 132, 133, 134 to the workpiston chamber 21 to drive the pistonand the associated wedge forwardlyto effect a crimping action, as earlier described. In thisY forwardmovement of the work piston, the return pistons 139 are ca rriedforwardly in their chambers 138. Any air trapped in the latter will beforced by this'action to flow back over passage 54 to the inlet 53. Whenthe work pistonvhas completed its forward stroke (as in Figs. 8, 8a),air pressure builds up in chamber 21 at the rear of the work piston andalso in a connected small antechamber 176 of the valve block. The latterchamber is normally sealed at one end by a pop-off valve 177 (Fig. 7a).The latter works in a relatively larger control valve chamber 178 of thevalve block and is loaded by a compression spring 179 to normally seatan O-ring retainer 190 over the open end of the ante-chamber 176. Theopposite end of the compression spring sleeves over a spring guide 181and abuts a shoulder at the end of the latter. A set screw 182 threadedthrough a cap plug 183 engages the spring guide and serves to adjust thepressure of spring 179 against the pop-off lvalve so as to predeterminethe build-up pressure required in the work piston chamber to unseat thepop-ol valve. The compression spring 179 projects through opposite openends of a control slide valve 184. The latter is slidable rearwardly ofthe pop-olf valve in the control valve chamber 178.

The control valve has a peripheral channel 185 which normallyregisterswith a passage 186 connected with the branch 173 leading fromthe throttle valve. An O- ring retainer 187 xed upon the control valvecarries an O-ring which normally seats upon a shoulder 180 formed by arear enlargement 188 of the control valve chamber. A compression spring189 disposed between this O-ring retainer and the -inner wall of the capplug 183 normally holds the O-ring seated on this shoulder, wherebypressure air in passage.186 is prevented from pass ing by way of channel185 through the control valve 8 t chamber to a passage 191 that leads tothe top end 192 of the distribution'valve chamber.

(Figs. 8, 8a.) As air pressure builds up in the work piston chamber,upon completion of the work stroke of the work piston 104,' it reaches adegree at which the pop-off valve 177 unseats. The pressure air then owsinto the control valve chamber ahead of the pop-of valve and acts uponthe relatively large O-ring retainer 190 of the pop-olf valve, whichretainer previously was disposed behind the shoulder 193. The pop-offvalve accordingly is forced back against the `load of spring 179 intoabutment with the control valve 184, and shifts the latter rearwardly.This unseats the O-ring retainer 187 from the shoulder 180, whereuponchannel 185 is caused to communicate passage 186 through the enlargement188 of the control valve chamber with passage 191. Pressure airthereupon flows to the top end 192 of the distribution valve chamber,and causes the distribution valve 124 to shift in the opposite directionback to normal position, whereupon the supply passage 53 is again closedto the work piston chamber 21 and the latter is again opened to vent136.' Since the pressure air in the cham bers 138 of the returnpistons139 is at all times at line pressure, the latter are caused to restoreand return the work piston following the return of the distributionvalve to normal position.

As the work piston restores, the air trapped at its rear vents throughpassages 134, 129, 136. The pop-oil? valve 177 next restores, as in Fig.9, under the load of its spring as the air pressure in chamber 21relaxes, but the control valve 184 is unable at this time to restoreunder the load of a spring 189 because the pressure of air in theenlarged portion 188 of the control valve chamber now acting against therelatively large O-ring retainer 187 is relatively stronger than theopposing force of spring 189 at this time. However, after the trigger1,71 is manually released, the throttle' valve 151 is reseated by'itsspring 164 to normal, as in Fig. 7a, whereupon air trapped in passages186, 173 flows around the stem of the throttle valve 151 to vent,whereupon the control valve restores.

Air trapped in the head end 192 of the distribution valve chamber and inthe connected passage 191 leaks around the outer diameter of the O-ringretainer 187 to the space at the rear thereof from where it escapesthrough vent holes 195 in the cap plug.

An interlock feature (Figs. 3 and 7) associates the trigger 171 with theoperation of the check valve 56, so that the trigger may not be actuatedwhile the push button 65 'of the check valve is depressed and the checkvalve is allowing flow of pressure air to the holding piston 39./ Thisis'a safety measure to prevent an accidental compressive movement of thewedge 99 while the jaws 33, 35 are temporarily held open by thedepressed condition of the push button 65. To this end, the port 58 fromthe check valve passage 57 leads to the chamber 59 in which the slidemember 61 works. The light compression spring 66 within the latterchamber holds this slide member in a position at the right so as touncover the open end of a vertical bore 197 which runs down through thewall of the housing to the outside. An interlock rod 198 hooked at itsbottom end in a cross hole 199 of the trigger, ex; tendsupwardly intothis bore. When the trigger-is-in its released condition, the upper endof the interlock rod is just below chamber 59, as in Fig. 3. Now, whenthe trigger is actuated, the rod will obviously be moved up into chamber59. If, however, the push button 65 has been depressed and is helddepressed, pressure air will' enter the chamber 59 and will force theinterlock slide member 61 to cover over the open end of the bore 197.While the latter condition exists, it is obvious that the triggermechanism cannot be actuated since the interlock rod will lbe blocked bythe slide member 61 from moving upward. When the push button isreleased,

pressure air trapped in the passage 62 leaks around the beveled nose ofthe slide member 61 and around the outer diameter of the push button tovent.

While an embodiment of the invention has been illustrated and describedabove, it is to be expressly understood that the invention is notlimited thereto. Various changes can be made in the design andarrangement of the parts without departing from the spirit and scope ofthe invention as the same will now be understood by those skilled `inthe art, and it is our intent, therefore, to claim the invention notonly as shown and described but also in all such forms and modicationsthereof as may be reasonably construed to be within the spirit of theinvention and the scope of the appended claims.

What is claimed is:

l. in a hand tool of the character described including a housing, a yokemember affixed to one end of the housing and having a stationary jaw,and a movable javt member closable upon the stationary jaw; a pistoncham ber formed in the housing, a holding piston movable in the latterchamber, in parallel relation to the movable jaw, an arm connecting thepiston with the movable jaw member for movement of the latter uponmovement of the piston, a spring load normally loading the piston in aparticular direction wherein the movable jaw member is held moved to aposition closed upon the stationary jaw, and control means forcontrolling admission of pressure air to the piston chamber to drive thepiston in the opposite direction against the spring load so as to movethe movable jaw member to open position.'

2. In a hand tool as in claim l, wherein the control means comprises apressure air supply line to the piston chamber, and a push buttonoperable check valve in the supply line having a normally closedposition.

3. In a hand tool as in claim l, wherein the movable jaw member ischaracterized by a tail portion having a shoulder at the end thereof,and wherein a latch block is slidable in the housing at right angles tothe jaw member and when the jaw member is moved to open position thelatch block is adapted to engage with the tail portion in front of theshoulder so as to restrain the movable jaw member against movement toclosed position, and wherein manually operable lever means is associatedwith the latch block for actuating the latter to and from engage.- mentwith the said shank portion.

4. In a hand tool as in claim 2, wherein the stationary jaw and movablejaw member have die elements adapted to receive therebetween workmaterial subsequent to movement of the movable jaw member to openposition, a power driven wedge is slidable in the housing, and means isprovided in the housing for engagement by the driven wedge fortransmitting a power movement of the wedge -to the movable jaw member soas to compressively close the latter upon the work material.

5. In a hand tool in claim 4, wherein the wedge is powered by a piston,valve means control a flow of pneumatic fluid to drive the piston, and amanually operable trigger is arranged for actuating the valve means.

6. In a hand tool as in claim 5, wherein interlock means is arranged toprevent operation of the trigger while the push button is in actuatedcondition, and comprises an interlock chamber 'in the housing, a memberslidable in the latter chamber, a rod connected at one end to thetrigger and normally slidable at the opposite end into a hole of theinterlock chamber upon slight actuation of the trigger, spring meansnormally holding the slidable member clear of the hole, and passagemeans to the interlock chamber connectable with the pressure air supplyline upon actuation of the push button, whereby the pressure airadmitted to the interlock chamber is adapted to move the slidable memberto a position over the hole to block entry of the rod into the latter.

7. ln the combination of a housing, a ram member slidable in the housingin a longitudinal direction, a power driven wedge movable in the housingin a longitudinal direction, and means for translating a longitudinalforward movement of the wedge into a corresponding movement of the rammember, wherein the translating means comprises a roller bearing member,a stationary support for the latter, a lever between the rear end of theram member and the bearing member, means associating the lever at oneend for pivot movement relative to the ram member, spring means normallysupporting the lever to the ram member in a horizontal plane wherein thelongitudinal axis of the lever is `aligned with that of the ram member,and a cam surface defining the opposite end of the lever, the leverbeing adapted to move rearwardly with the ram member upon a rearwardmovement of the latter whereby the cam surface is caused to abut andride downwardly over the bearing member and cause the lever to pivotdownward as it does so, and the lever being adapted to pivot upwards toits horizontal position upon a forward movement of the wedge against theunderside thereof whereby the cam end of the lever is caused to rideupwardly over the surface of the bearing member and the ram member iscaused to move forwardly as the cam end of the lever so rides.

8. In the combination as in claim 7, wherein the means associating thelever with the ram member for pivot movement comprises a rounded nose atthe forward end of the lever abutting the rear of the ram member, aspring plate mounted latop the lever yand having a lip extensionoverlying the ram member, and an under lip extension of the leverunderlying the ram member, the upper and lower lips serving to preventthe lever from slipping free of the ram member in a vertical plane.

9. In the combination as in claim 8, wherein an abutment of the housingoverlies the lever, being in close proximity to the lever when thelatter is in a horizontal plane, the lever being adapted to strike thisabutment in the event of an abnormal overrise thereof above itshorizontal plane, and the lip extension of the spring plate adapted toresiliently react against the surface of the ram member in the event ofsuch overrise action of the lever.

l0. In the combination as in claim 7, wherein the lever is characterizedby depending roller means engageable by the wedge in the forward slidingmovement of the latter.

11. In a crimping tool including an elongated housing having a pistonchamber and a thickened wall area forwardly of the latter, the wall areahaving elongated bores therein parallel to the piston chamber, a workpiston movable in the piston chamber, and a pair of elongated rodsparallel to the longitudinal axis of the work piston and fixed at oneend to diametrically opposite portions of the forward face of the latterpiston; a pair of return pistons formed at the opposite ends of the rodsand adapted to move in the said bores in the said wall area, a pressureair inlet to the housing, a first branch passage from the inlet leadingdirectly to the said bores for continuously conducting pressure air fromthe inlet to drive the return pistons in a rearward direction relativeto the housing, a second branch passage from the inlet for conductingpressure air to the piston chamber to drive the work piston forwardly,the return pistons having a total diameter relatively less than that ofthe work piston whereby pressure air from the inlet conductedsimultaneously to both the return pistons and the work piston will drivethe latter forwardly, pressure air flow control valve means associatedwith the second branch passage for controlling a flow of pressure airfrom the inlet to the piston chamber so as to cause the work piston tomove in a forward direction, manually operable means for actuating thesaid valve means, and other valve means responsive to a predeterminedpressure in the piston chamber at the end of the forward stroke of thework piston for automatically shutting off the flow of pressure air fromthe second branch passage to the piston chamber and communicating thepiston chamber with vent.

12. In' the combination comprising' a housing, a ram` member slidabletherein, a wedge'element slidable forwardly and rearwardly in thehousing, means disp'c'xsed` ber, and means providing roller support tothe wedge;i element in' its sliding movement; wherein thef latter meanscomprises a trackway formed in the housingbelow the path of movement ofthe wedge, a'pair" of shoulders'bordering the trackway, and a ladderroller cage" having a thick center guide rail movable" in the trackwayand having a series of roller pins' projecting from opposite sides ofthe rail adapted to roll upon" the shoulders, and the wedge elementhaving'y a pair of 'depending longitudinal shoulders contactingthe`roller pins and adapted to ride upon the latter as the'wedgc moves.

13. In the combination as in claim 12, whereinthe ladder roller cage hasa normal position relative to the trackway and reacts to the slidingmovement of'the wedge to follow in the direction of the latter, whereinthe ladder roller cage has an upstanding ear at its rear, and the wedgehas an under shoulder engageable with this`ear upon a rearward movementof the wedge, where by this engagement the ladder cage is adapted to bereturned to its normal position. p

14. In the combination as in claim 13, wherein the ladder roller cage islonger than the longitudinal shoulders ofthe wedge, a forward portion ofthese shoulders normally rests upon the roller pins and a rear portionoverhangs the rear end of the ladder roller cage, and means is providedto cause the ladder roller cage to move relatively slower than the wedgein reaction to the movement of the latter whereby the longitudinalshoulders`of'the wedge are progressively caused to'fully ride upon theroller pins of the ladder cage. p

l5. In a pneumatically powered tool including a Work piston, a pluralityof return pistons attached to the Work piston for movement together withthe work piston'and having a total effective area relatively less thanthat of the work piston, a housing providing chambers for the workpiston and the return pistons and having a valve block and a pressureair inlet to the valveblock common to the chambers of the work pistonand of the return'pistons; valve means actuable for admitting pressureair from the inlet to the chamber of the Work piston to drive the workpiston on a power stroke andV normally blocking such admission ofpressure air,'manV ually operated means for actuating the valve means-toadmit such pressure air to the work piston chamber,

and other means responsive to a predeterminedvalueV of pressure air inthe work piston chamber atter'com'- pletion of the power stroke of thework piston to render the'valve means ineffective to supply furtherpressure air to the work piston, whereby pressure air'from the' commoninlet to the return pistons is effective to operate the latter to returnthe work piston.

16. In a pneumatically powered tool includinga Work piston, and a pairof return pistons attached to the Work piston for movement together withthe latter and hav' ing a total effective area relatively less than thatof i the work piston; a common source of pressure air connectedvto boththe work piston and the return pistons,V

pressure air to the return pistons whereby the return pistons yaredriven to return the work piston, manually operable means for placinglthe control means in its rst condition, and means responsive to apredetermined degree'of pressure arising at the rear of the work pistonafter completion of the Work stroke of the work piston to placethecontrol means in its second condition.

17. In a'pneumaiically powered tool including a workVpistorreliecti'veupon a power stroke to actuate one element relative toanother, a pair of return pistons attached to the work piston formovement together with the latter and having an effective arearelatively less than that of the work piston, a housing providingseparate piston chambers for the work piston and the return pistons, avalve block at one end of the housing, a pressure air inlet to the blockbeing common to the chambers of' the work piston and of the returnpistons, control' means normally stopping low of pressure air from theinlet to the chamber of the work piston and not to the chambers of thereturn pistons, manually operable means associated with the controlmeans to actuate the latter to discontinue the stoppage of iiow ofpressure air to the chamber of the work piston whereby the differentialin pressures of air acting on both the return pistons and the workpiston causes the Work piston to execute a power stroke carrying thereturn pistons with it, and other means automatically responsive to apredetermined development of pressure in the work piston chamber aftercompletion of the said power stroke to actuate the control means toagain stop ow of pressure air to the chamber of the work piston and notto the return pistons'whereby the return pistons are caused to move inthe opposite direction and to carry the work piston with them.

18.' Inthe combination of a to'ol of the character described including apneumatically powered work piston movable in a piston chamber, and asource of pressure air; a systm'of interacting slide valves interposedbetween'thesource and the piston chamber, comprising meansnormallyapplying pressure air from the source to the'valve system whereby thelatter is maintained in a normal condition blocking ow of pressure airfrom the source to the piston chamber, manually operable means connectedto the valve'system effective in an operated condition to vary thedirectional application of pressure air from the source vto the valvesystem whereby the latter is caused to be shifted to a second conditionallowing ow of pressurel air from the source to the piston chamber todrive the piston over a power stroke, means responsive to apredetermined build-up of air pressure in the piston chamber subsequentto the power stroke of the piston to vary the directional application ofpressure air from the source to the valve system so as to shift thellatter to a third condition wherein the valve system discontinues ow ofpressure air from the source to the piston chamber, and other meanseffective upon manual release of the manually operated means to' causeVa directional variation of the application of pressure air from 'thesource to the valve system to restorethe latter to its normal condition.

References Cited in the lile of this patent UNITED STATES PATENTS2,158,855 Eby et al. May 16, 1939 2,254,613 Matthysse Sept. 2, 19412,600,860 Dupre lune 17, 1952 2,633,161 Schultz et al. Mar. 31, 19532,693,218 Freedom Nov. 2, 1954 2,722,859 Stoltz Nov. 8, 1955

